Sunday, November 04, 2012

Who Do You Want Up When You Need to Get a Run Home?

Fans and baseball insiders have long been enamored by the RBI statistic. While it is a team statistic which can be deceptive when used for evaluating players, it is easy to see why players are more interested in RBI than numbers such as slugging average or OPS. When a batter comes up with a runner in scoring position, he is not thinking about improving his wOBA, rather he is focused on getting the run home.

Fans like the RBI metric because it is concrete, something they can easily see while watching games. It doesn't involve weighting offensive events or theoretical runs scored or anything abstract or complex.

The Runs Batted In metric is limited in what it tells us about a player's overall value, but the ability of a player to drive in runs is an important trait. A manager's perception of a batters capacity to drive in runs influences how he constructs his line-up. He generally wants to put his best RBI men (which are typically power hitters) in a position where they will have lots of opportunities to drive home base runners.

A players ability to collect RBI can also affect in-game strategy. For example, a player who is good at scoring base runners is more likely to swing away when there are runners on base rather than to try to work a walk. In the same situation, the opposing team will not want to give him good pitches to hit.

So, driving in runs is an important part of the game and should be tracked, but some players have many more chances to get RBI than others. So much depends on who is batting in front of a particular player. Thus, opportunities need to be considered if we are going to use RBI to assess players.

This is where the RBI opportunity statistics
at Baseball Prospectus come into play. Using that data, we can determine how many runners were on
base in a player's plate appearances and how many of those runners scored. For example, there were 444 runners on base (ROB) in all of Miguel Cabrera's plate appearances in 2012 and 95 of them scored. The 95 is referred to as Others Batted In (OBI) and does not include a hitter batting himself in with a home run. Dividing 95 by 444 yields an OBI Percentage (OBI%) of 21.4. The league average OBI% in 2012 was 13.8.

The OBI% statistic is not a measure of how clutch a player is. It is a combination of hitting for average, hitting for power, situational hitting in a given year and how he is pitched to. One problem with OBI% is that many players don't have a very large number of plate appearances with runners on base in a given season, so small sample size luck may be a factor. For example, a given batter may have had an inordinate number of opportunities with runners on third base in one season whereas another hitter may have had most of his chances with a runner on first only.

Therefore, it useful to look at multiple years of data. So, I took data from 2010-2012 and calculated OBI% for all players with at least 1,000 plate appearances during that period. The top 25 in MLB are listed in Table 1 below. So, who do you want at the plate when you need to score a base runner? Free Agent slugger Josh Hamilton leads with a 20.8 OBI% followed by Rockies outfielder Carlos Gonzalez (20.8%). Cabrera is sixth at 18.7%.

There are not many surprises at the top of the list, but notice that one of the games greatest hitters over the past three years is missing. Angels first baseman Albert Pujols is nowhere to be found, not because he doesn't have a talent for getting runners home, but because teams tend not to give him a chance to do so. In 2010 alone, he received 38 intentional walks while playing for the Cardinals and those count against him. Cabrera's OBI% has also been negatively influenced by intentional walks.

Is it fair to penalize a player for intentional walks? I struggled with this one, but ultimately I decided it's OK. It certainly would be unfair if we were answering a question about the game's best hitters. However, the question is who do you want at the plate when you need to get a run home? In that case, an intentional walk does not help, so it's reasonable to consider it a failure in addressing the question at hand.

One of the most interesting names in the table is the much maligned Delmon Young. Among 234 qualifiers, he finished 23rd with a 17.1 OBI%. Your first reaction might be that it is all due to his 2010 season where he had a robust 20.4 OBI, but he also finished at 17.2 in 2011. If you want to go back another year, then it's 18.8 in 2009. So, it does seem as if he has had a knack for getting runners home.

One reason for the high OBI% is that Young is a free swinger, who hits for a reasonably good average. One of the few benefits of not drawing walks is it gives a player more chances to drive in runs as walks don't usually do the trick. Another explanation is that Young has hit a lot better over the course of his career with runners in scoring position (.793 OPS) compared to bases empty (.716).

It all adds up to Young being successful at getting runners home with his at bats. This doesn't make up for his general propensity to make outs and not get on base or his poor defense. It might, however, justify his batting fifth all year behind two of the best hitters in the game. It didn't work this year as his OBI% was only 13.5, but he does seem to have an "RBI ability".

In case this analysis gives anyone any second thoughts at all about the departure of Young, keep in mind that he'll be replaced by Victor Martinez who had an even better OBI% (18.7%) and does everything else with the bat a lot better than Young.